Metal pot for typographical machines



Oct-.15, 1929. LE RoY'w. WILLIS METAL POT FOR TYPOGRAPHICAL MACHINES Filed June 25, 1928 qyW IN VEN TOR. Will's,

A TTORNEYi Patented Get. 15, 1929 mama UNITED STATES PATENT erries LE ROY W. WILLIS, 6F BROOKLYN, NEW YORK, AS SIGNOR T INTERTYPE CORPORA- TION, OF NEW YORK, N. Y., A GORPORATION OF NEW YORK METAL POT FOR TYFOGBAPHICAL MAGHINES Application filed June 25, 1928.- Serial No.. 288,103.

The present invention relates to improve- I ments in metal pots of the kind used in typographical machines, and more especially those of the general class shown and described in Letters Patent No. 436,532 granted on September 16, 1890 to O. Mergenthaler, wherein composed lines of character-bearing matrices are presented to one face of a mold and the mouth-piece of a metal pot is brought against the opposite mold face, and a pump 'or plunger then operates to force molten metal fromthe well of the metal pot throu h a throat leading therefrom and through t e metal pot mouth-piece and into the mold to cast a type bar or slug therein.

One of the objects of the invention is to provide means whereby the normal level of the molten metal in the throat of the metal pot is always maintained automatically at a substantially constant height and in relatively close proximity to the mold-engaging mouth-piece, notwithstanding variations in the level of the molten metal in the metal pot proper, the amount of air contained in the metal pot mouth-piece above the metal therein being thus reduced to a minimum and the necessity of using metal feeders 0F other means for maintaining a constant normal level of the molten metal'is avoided. By thus minimizing the amount of air normally contained in the metal pot throat above the -molten metal therein, the amount of air which must be vented from the mold during the injection of the molten metal therein is reduced to the extent that thetiformation of voids or air holes in the type bars or slugs, due to the trapping of air in the mold, and which if present, would weaken the slug and render it liable to cave in under the relatively heavy impression pressures used in the commonly used dry mat printing process, 1s avoided, the present invention en a ling type bars or slugs to be produced whlch are un1- formly solid or substantially so and free of weakening air holes.

Another object is to provide means whereby the molten metal in the metal pot throat, after each casting operation, is brought to such a level as will avoid spilling of the molten metal through the metal pot mouth- 5 plece during the tilting movements of the metal pot incident to the regular operations of the machine, such means being preferably ad ustable to enable it to maintain the molten metal at a desired constant normal level.

A further object of the invention is to provlde valve means for accomplishing the above stated objects, which valve means is adapted to be easily inserted in the pump well of any metal pot of the usual or conventional form, and which will require no additional or auxillary operating mechanism, it bein controlledand operated by the usual meta pot plunger, and to provide valve means WhlCh will not require cleaning and will not deteriorate under the influence of the heat of the molten metal.

To these and other ends, the invention cons sts in certain improvements and combination and arrangements of parts, all as will be hereinafter more fully described, the features' of novelty being pointed out particularly in the claims at the end of the specification. ;In, the accompanying drawings I Fig. 1 is a sectional view in perspective of a metal pot embodying the present invention, the section being taken vertically and centrally through the metal pot well and throat; 5"

Fig. 2 is a fragmentary sectional view in perspective showing a portion of the valve seat, preferably used;

Fig. 3 is a fragmentary view of another portion of the valve seat showing the preferred means for securing it in position in the metal pot well; and

Fig. 4 is a sectional view of the metal pot well, the metal injecting plunger and the valve means, showing diagrammatically the operation of the valve means.

Similar parts are designated by the same reference characters in the different views.

The present invention is applicable generally to metal pots of the kinds used in line casting and other typographical machines and employing a reciprocatory plunger which operates at an appropriate time in the cycle of operation of the machine to inject molten metal into the mold to cast a type bar or slug therein, the general construction of such a machine and its metal pot and the means for operating the plunger of the metal pot being well known in the art and set forth in the patent hereinbefore referred to.

The preferred embodiment of the invention is shown in the accompnying drawing and will be hereinafter described in detail, but it is to be understood that means equivalent to thatshown might be used in earl-1ying out the invention, and such is included within the scope of the claims.

In the present instance, 1 represents the metal-pot which is generally similar in'form to those commonly used in line casting machines, the pot-having a reservoir 2 adapted to contain asupply of molten metal 00 which is to be used in casting the type bars or slugs, it being understood that burners or other heating means are commonly used tomaintain the metal in the pot in a moltenstate. A pump cylinder 3 is formed usually within the "metal potso that it will be submerged in the molten metal therein, and a plunger 4 is'mounted to reciprocate in the cylinder, the plunger being operated by a rod 5 which is pivotally connected at its lower end to the plunger and is pivotally connected toward its upper end, as by the pivot pin 6 to an arm 7 which is always acted on by a spring 8 and interposed rod 9 in a direction to force the plunger 4 downwardly, the, arm 7 how-'- ever being normally held in' raised position against the action of the spring 8 by a cam "which has a drop or recess therein which causes the arm 7 to suddenly move downwardly when the machine reaches the point in its cycle of operation when a cast is to be made. Molten metal is supplied to the under side of'the plunger 4 from the reservoir 2, through the usual port 10 which extends through a wall of the cylinder 3 and is uncovered by the lower edge of the plunger when the latter is in its normal elevated position, so that molten metal may then flow from the reservoir 2 through this port and into the cylinder below the plunger'to replace metal taken by the mold in' the previous casting operation. a

The well 11 at the bottom of the cylinder communicates with a throat which leads upwardly and forwardly therefrom and .the throat communicates at its upper forward end with a mouth-piece 13 which may be of the usual construction having perforations arranged on a level with the mold cavity against the rear side of which the mouthpiece is adapted to fit during the casting operation, so that descent of the plunger will force molten metal from the well 11 and through the throat 12 and the mouth-piece 13 into the mold and against a line of'character bearing matrices which are then presented to the front face of the mold, as is usual in machines of this general class. It will be understood that the metal pot is mounted to tilt forwardly to bring the mouthpiece thereof against the mold, preparatory to a casting operationand to tilt rearwardly to remove its mouth-piece from contact with the mold, after a cast has been made, as is usual in machines of this general class.

Heretofore, the normal level of the molten metal in the metal pot throat depended upon the level of the molten metal in the metal pot reservoir, and in consequence, the metal 7 the throat must be vented in advance of the molten metal to enable the molten metal to enter and fill the mold, and when a large body of air is present in the upper end of the throat, the amount of air to be vented from the mold is such that a considerable portion of the air becomes trapped ,in the .mold, resulting in the casting of slugs with large air holes which extend'suificiently close to thecharacter-bearing edge of the type bars or slugs to weaken the same and thus-render them liable to cave in under the relativelymachine proceeded, due

heavy pressui'e used in the dry mat printing a process now extensively employed in newspaper and other printing. Also, it has been found that the type faces of the characters on slugs produced under the influence of trapped air are often imperfect. Automatic metal feeders have been proposed for feeding metal to the metal pot reservoir to replace that used in the casting of type bars or slugs, in an effort to maintain a substantially constant metal level in the metal pot reservoir, but such metal feeders are complicated and expensive and otherwise objectionable.

The present invention provides relatively simple and effective means for maintaining the molten metal in the metal pot throat at a substantially constant level which is sufficiently high to be always in close proximity to the metal pot mouth-piece, whereby a minimum amount of air will be contained in the throat above the molten metal therein, so that uniformly solid type bars or slugs substanthe useof automatic metal feeders and prefera-bly, the means provided by the present invention for accomplishing these results is controlled by the regular known form of metal pot plunger so that additional or auxiliary operating means therefore is unnecessary. The means provided by the present invention always maintains a substantially constant metal'level in the metal pot throat irre spective of variations in the level of the molten metal in the metal pot proper, and the normal metal level in the throat is such that spillin of ,molten metal through the mouthplece during the tilting movements of the metal pot incident to the usual operation of the machine, is avoided. An adjustable stop screw is preferably used to limit downstroke of plunger so that its stroke will be suflicient to displace enough metalto form the largest desired slug yet terminate the down stroke before the plunger strikes the valve in the bottom of the well.

The metal level controlling means, in its preferred form and as shown in the present instance, comprises a valve 14 and a valve seat 15, the valve and valve seat being placed in the well 11 of the metal pot. The valve and valve seat may be readily inserted in the well of any metal pot of the usual conventional form, the valve 14 being preferably in the form of a ball or sphere and the valve seat 15 being, for exam le, fitted into an annular recess 16 formed in the lower side of a ring 17 which may be composed of metal, althou h the seat and its supporting ring vmay e formed in one piece of the same material, the

outer circumference of "the seat supporting ring being preferably cylindrical and of a normal diameter slightly smaller than the bore of the pump cylinder 3 so that this ring may be dro pad or pushed down in the cylinder, after t e ball 14 hasheen dropped into the well 11, and in order to provide a support for the ring, a suitablenumber of screws 18 threading a screw 20 into the ring, the head are threaded through the ring from the top thereof and have le s which extend downwardly, the screws being individually adjustable from their upper ends so that the lower ends of the screws may be brought against the unevenly cast surface forming the bottom of the well, the screws when-properly adjusted providing legs to evenly support the ring 15 1n position. The ring is secured against displacement preferably by forming a radial slot 19 in its circumference and of the screw being conical or tapered and arranged to bear against the portions of the ring at oppositesldes of the slot19, so that tightening of'the screw will spread or ex-. pand the ring circumferentially, thus increasing its diameter suflic-iently to cause it to fit tightly within the bore of the cylinder engagp y prevent rising of the ball sufiiciently composed of a material or composition hav-- ing a high heat resisting value and which will not disintegrate or warp when immersed in the molten metal and which has no affinity for themetal, the valve being composed for example of a composition known commercially as eleotrobestos which consists of white clay, asbestos fiber and magnesia having a specific gravit of 1.92, and the seat may be composed o a composition known commercially as transite which consists of a mineral cement, asbestos fiber and magnesia having a specific gravity of 2.00, or the ball and seat may both be composed of either of these compositions or of compositions having similar properties. The ball-like valve is lapped against the seat 15 during manufacture to-form a metal tight joint therewith when seated, and the above named properties of the valve and. seat will insure the maintenance of a perfect joint between the valve and its seat for an indefinite period and cleaning of the valve or its seat will be unnecessary as there will .be "no tendency of. the molten metal to coat or adhere to either the valve or its seat. The relatively. low specific gravity of the compositionconstitutin the valve will give the valve a substantial egree of buoyancy in the molten metal which has a relatively high specific avity, and as the valve is always submerge in the molten metal, it

will always have a tendency to rise therein. I

The lower ends of the screws 18 are so spaced around the valve that they will avoid interference with the free movements thereof in a direction toward and from its seat but will confine the valve against displacement fromring 17, when the plunger is at the lower limitof its downward-or metal injecting stroke, the screw being so adjusted that it will then thetop of the ball-like valve 14 and there to engage and form a fluid-tight joint with the seat.

The mode of operation of a metal pot constructed as hereinbefore described is as follows. When the plunger 4 is in its normal fully raised position. as shown in Fig. 1, the ball-like valve 14 will be held up against the seat 15 by the buoyancy of the valve in the molten metal and by the overbalance of by v draulic pressure acting on its under side over that acting on its upper side, the hydraulic pressure acting on the lower side of the valve being then free to flow unobstructcdly by a drop or recess being produced by the column of molten metal contained in the spout 12 up to the level h while the hydrostatic pressure actin on the upper side of the valve is produce by the height of the molten metal contained in the reservoir 2 up to the relatively lower level 72/, the metal in the reservoir 2 being free to flow into the cylinder 3 and beneath the plunger when the latter is fully raised, as the port 10 in the side of the cylinder is then uncovered by the plunger. I

When the casting point is reached in the operation of the machine, the arm 7 is released in its controlling cam, and the plunger 4 is then forced downwardly under the action of the spring 8. The down stroke of the plunger forces the molten metal contained in the cylinder 3 downwardly, thus unseating the valve 14 and pushing it downwardly into the dotted line position shown diagrammatically in Fig. 4, the molten metal through the relatively large annular passageway formed between the valve and its seat and up through the throat 12 and through the mouthpiece 13 into the mold to fill the same and thus cast the type bar or slug. \Vhen the mold has been filled with molten metal, the plunger 4 will have reached its lowermost position as.

shown in Fig. 4 and will come to rest momentarily in that position whereby the pressures in the cylinder 3 and throat 12 will become equalized and the buoyancy of the valve 14 will tend to return the valve to its seat, but

the screw 21 in the bottom of the plunger is so adjusted that it will contact with the top of the ballasthe latter moves toward its seat and will thereby prevent the ball from seating entirely or tightly, as is indicated by the full lines in Fig. 4, and the valve will be thus held unseated until the plunger has reshown in treated upwardly for a slight distance, this upward movement of the plunger being produced by the rise in the cam commonly used to control the pump plunger in machines of this class, and the slight upward or retreating movement of the plunger which carries the screw 21 upwardly and thus allows the valve to seat tightly draws back the metal in the throat 12 sufficiently to prevent spilling of the metal-from the metal pot mouth-piece during the forward and rearward tiltin movements of the metal pot preceding an following the casting operation, the metal 111 the throat being lowered for example substantially to the line it indicated in Fig. 1, the metal being there shown at a level slightly below or in rear of the mouth-piece. The continued retraction or upward stroke of the plunger brings it to the normal position Fig. 1, the plunger being permitted to rise notwithstanding that the valve is tightly seated, by the clearance fit of the plunger in its cylinder which allows enough metal to pass to counteract the vacuum pressure created upon upward stroke-of the plunger after the valve has closed. At nearly full upward stroke of the plunger, the port 10 in the side of the cylinder is then uncovered so that metal from the reservoir 2 may flow freely into the cylinder between the valve and the under side of the plunger to establish normal equilibrium within the pot chamber 2, ready for the next cast.

'An adjustable stop screw 7 is preferably provided for the purpose of limiting the downward or working stroke of the plunger to the proper degree, depending on the size of the slugs being cast, this screw being, for example, threaded into the under side of the plunger actuating lever 7 in a position where it will abut against the top of the metal pot, or the usual cover thereon, the head of the screw being shaped to receive a wrench or screw driver by which it may beadjusted so that it will stop the downward or metal injecting stroke of the plunger when the lat-- pot throat notwithstanding variations in the.

level of the molten metal in the supply reservoir 2, and the molten metal in the throat may be maintained at all times within the closest proximity to the back of the metal pot mouth-piece so that a minimum amount of air is present above the molten metal in the threat. The screw 21 which controls the seating of the ball after the casting operation enables the molten metal to recede in the throat sufiiciently to avoid spilling of the molten metal from the metal pot mouthpiece during the tilting motions of the metal pot, and as this screw is adjustable, the normal level of the metal in the throat may be determined accurately, and when the adjustment is made, the level of the metal in the throat will be substantially constant.

Type bars or slugs produced with a metal pot embodying the present invention are uniformly solid or substantially free from weakening air holes, whether the slugs are of the largest or the smallest common size, so

that they will withstand the heavy impres- While the invention is particularly useful in connection with the production of slugs intended to be used in the dry mat printing 7 process ,it is obvious that the invention is not so limited as it enables slugs to be cast which have type faces which are formed more perfectly and are free of imperfections such as those produced by the mixing of air with the portions of the metal which form the type face. While it is preferable to construct the ball valve and its seat of a material or composition having no affinity for the molten type metal, as the valve then is not likely to become leaky or to require cleaning, the valve or its seat or both may if desired be made of metal or other material having a higher melting point and lower specific' gravity than that of the molten type metal with satisfactory results, although 00- casional cleaning of the valve and its seat may becomenecessary. Y

I claim as my invention: I 1. In a metal pot for typographical machinesv having a reservoir for molten metal, an upwardly extending metal injecting spout communicating with said reservoir to receive metal therefrom and having a metal discharge mouth at its upper end, and a reciprocatory plunger for forcing metal upwardly through said spout, valve means interposed in the path of metal flow between the plunger I and the mouth of the spout'and movable into closed position during the return stroke of the plunger to check the back flow of metal in the spout and thereby maintain the metal in the spout at a higher level than that in the reservoir. 7

2. In a metal pot for typographical machines having a metal injecting spout provided with a discharge mouth, and a reciprocatory plunger for forcing molten metal therethrough, a valve interposed in the path of metal flow between the plun er and the 1 mouth of the spout, a valve seat etween the valve and 'plunger and toward which the p valve is movable during the return stroke of the plunger, and means on the plunger engaging the valve and holding it away from said seat while the plunger is at the end of its metal injecting stroke. 3. In a metal pot for typographical machines having a metal injecting spout provided with a discharge mouth and a reciprocatory plunger for forcing molten metal therethrough, a valveinterposed in the path of metal fiowbetween the plunger and the mouth, of the spout, a valve seat between the valve and plunger and toward which the valve is movable during the return stroke of the plunger, and a screw on and adjustable in the direction of movement of the plunger for variably holding the valve away from said seat while-the plunger is toward the end of its metal injecting stroke to control the normal level of the metal in the spout.-

4. In a metal pot of the class having a metal well, a metal injecting spout leading therefrom and a plunger for forcing metal from said well through the spout, a valve seat in the well between the plunger and spout, and a valve buoyant in and immersed in the molten metal in the well and at the lower side of said seat.

seating against the underside of the valve seat, and a part carried by the plunger and cooperative with the valve to hold the valve in unseated position while the plunger is at the commencement of its return stroke.

6. In a metal pot of the class described having a metal well, a metal injecting spout, and a plunger for forcing molten metal from the well and through the spout, a valve seat located in the well between the plunger and spout, a valve buoyant in the molten metal and resting against the under side of said seat, and a. screw carried by, the plunger and adjust-able in the direction of its movement and cooperative with the valve to hold it in unseated position while the plunger is at the commencement of its return stroke to control the normal level of the metal in the spout.

7. In a metal pot of the class having a metal well, a metal injecting spout, and a plunger for forcing molten metal from the well and through the spout, a valve seat and cooperative valve located in said well control the back flow of molten metal in the spout, said seat and valve being composed of heat resisting material having substantially no afiinity for the molten metal.

8. In a metal pot of the class having a metal well, a metalinjecting spout, and a lunger for forcing molten metal from the well and through the spout, a valve and cooperative valve seat located in the well for controlling back flow of metal therein, and a supporting ring for the seat, said ring be ng expansible and having means for expandmg it against the wall of the well to secure it in position therein.

'9. In a metal pot of the class having a metal well, a metal injecting spout, and a plunger for forcing molten metal from the well and through the spout, a valve and cooperative seat located inthe well for controlling back flow of metal in the spout, and means adjustable from the top of the valve seat and extending downwardly through the valve seat and located at intervals in its c1rcumference, said means being engageable at their lower ends with the bottom of thewell.

10. In a metal pot of the class havinga metal well, a metal-injecting spout, and a plunger for forcing molten metal from the well and through the spout, a valve and c0- operative seat located in the well for controlling back flow of metal in the spout, and screws extending downwardly from the valve seat at intervals in its circumference and engageable at their lower ends with the bottom of the well to position the seat therein, the valve bein accommodated between and confined by said screws.

In testimony whereof I have hereunto set my hand.

LE ROY W. WILLIS. 

